So put another engine back together for my S4 TII year 87. I am having the same issues as the previous engine. Before I didn't have any idle and it would misfire alot. I believed it to be the engine since i only took the rear half apart and rebuilt it. So i did it the right way. Having same issues again. I believe them to be electrical

First issue. When first starting i did not have a tach signal. but when i pulled the EGI INJ fuse out the signal would come back up, and when i put it back in there would be no tach signal again.

Second issue. Car is not idling and running very rich causing it to flood constantly. 720cc primary and secondary with rtek 1.8.

Third Issue. Car misfires constantly.

S4 TII stock engine.
Removed Emissions
Rtek 1.8
720cc primary
720cc secondary
Rb turboback
S5 manifold
S5 Turbo
Koyo Rad
MSD 6A
Koyo Rad

 

Check wiring harness, sorry to be so unspecific but you should inspect the harness if you are having problems such has tach not working with fuse in, but works with fuse out. You could have a short somewhere or just bad internal connection in the harness itself. You can probably follow the FSM wiring diagrams to help you narrow it down, but if your harness is in bad condition i wouldn't be surprised if your car is running the way it is.

But to start off the lazy way, did you try to swap another PCM (ECU) and see if that worked out?

 

just got this ecu back from rtek, they test everything before sending it out so i assume it works good. first time ever installed.

when i have time to work on the car, iam going to bypass the MSD box. I was talking to a friend and he says they aren't that great if you daily drive your vehicle, and burn out often. I bought it used so yea.

Also doesnt the tach signal come off the leading coil? or something like that

 

Well I am not much help but I can tell you the tach signal comes off the trailling coil.

 

check vac lines to omp, also check injector plugs to make sure they are going to the right injectors........

 

OMP is disabled running premix.

Let me verify the injector wiring. The injectors for the front housing have the plug for a Water temp sensor. and the rear housing injectors have the wire for the idle stuff.

Longer wire to secondaries and shorter to the primaries?